Abstract: Provided herein are methods for identifying compounds that are inhibitors of a calcium-activated chloride channel. Aminothiophene and aminothiazole compounds, and compositions comprising these compounds, described herein that inhibit efflux of chloride through a calcium-activated chloride channel are useful for treating diseases, disorders, and sequalae of diseases, disorders, and conditions that are associated with aberrantly increased chloride and fluid secretion, for example, secretory diarrhea.

Abstract: Provided herein are small molecule compounds that alter the transport activity of solute transporters, particularly urea transporters. The compounds described herein belong to the phenylsulfoxyoxazole, phenylsulfoxyimidazole, phenylsulfoxythiazole class of compounds. The compounds described herein are useful for increasing solute clearance in states of fluid overload and for treating cardiovascular, renal, and metabolic diseases, disorders, and conditions. Methods for identifying and using these agents that inhibit urea transporters are described herein.

Abstract: The invention provides compositions, pharmaceutical preparations and methods for increasing activity of a mutant cystic fibrosis transmembrane conductance regulator protein (mutant-CFTR). The compositions pharmaceutical preparations and methods are useful for the study and treatment of disorders associated with mutant-CFTR, such as cystic fibrosis. The compositions and pharmaceutical preparations of the invention may comprise one or more bithiazole-containing compounds of the invention, or an analog or derivative thereof.

Abstract: Provided herein are methods for identifying and characterizing agents that alter the volume of a cell. Methods are provided for rapid screening and identification of an agent that alters the capability of a small, neutrally charged solute transporter to transport the solute across a cell membrane. The methods described herein may be used to identify and characterize inhibitors of urea transporters, to identify and characterize inhibitors of aquaporins, and to identify and characterize inhibitors of other small, neutrally charged solutes such as glucose.

Abstract: Provided herein are divalent hydrazide-polyethylene glycol conjugates that inhibit the ion transport activity of a cystic fibrosis transmembrane conductance regulator (CFTR). The conjugates described herein are useful for treating diseases, disorders, and sequelae of diseases, disorders, and conditions that are associated with aberrantly increased CFTR activity, for example, secretory diarrhea.

Abstract: Provided herein are bioactive agents comprising a compound that inhibits the ion transport activity of a cystic fibrosis transmembrane conductance regulator (CFTR) and that is linked to a macromolecule that interacts with a cell that expresses CFTR. The bioactive agents described herein are useful for treating diseases, disorders, and sequelae of diseases, disorders, and conditions that are associated with aberrantly increased CFTR activity, for example, secretory diarrhea.

Abstract: The invention provides methods and compositions for measuring ion concentration inside a cell by measuring fluorescence of a compound of the general formula I. In particular embodiments, the measured ion is halide, particularly iodide, the cell contains a functional anion transport protein or channel, the method measures a change in fluorescence as a function of a predetermined condition such as the presence of a predetermined amount of a candidate modulator of ion transport in the cell (e.g. for drug screening) or the expression by the cell of a transgene (e.g. to assess the efficacy of gene therapy).